Fiber that is wound on a bobbin normal (at right angles) to the bobbin axes will be payed out, or dispensed, in a spiral from a missile which uses optical fibers to control the missile flight to a target. Fiber that is wound on the bobbin with a full twist will be dispensed in a straight line from the missile. Full twist is defined as the amount of twist required to cause the fiber to be dispensed in a straight line.
Fiber that is payed out in a spiral is more likely to develop "kinks" and break than is fiber that is payed out in a straight line. From the standpoint of transmission losses due to changes in indices of refraction and losses due to microbending of the fiber, there will be certain advantages realized from optimizing the amount of twist on the fiber.
Fiber that is wound on the bobbin should be wound in such a manner as to preclude skips and/or overlays for each layer of fiber. After sufficient stepback from each end, the succeeding layers of fiber should be accomplished using a preset constant tension and twist on the fiber. Failure to wind the fiber in this manner will result in high losses (attenuation) due to microbending at crossover points and will impede the fiber payoff process due to nonuniformity of the fiber windings.
The present invention in a device which allows each turn of fiber to be wound on the bobbin without skips and overlays. This task is performed independent of servo drive motor deadband or backlash.